Left: Rears tower sprayer has adjustable airflow doors on the tower. Center: This Durand Wayland sprayer is equipped with ultrasonic sensing eyes to detect trees—reducing spray up to 25 percent in Cornell trials. Right: Sardi fans fitted to a vertical mast allows spray to be directed into the tree canopy at higher levels.
PHOTOS COURTESY OF ANDREW LANDERS
Before you buy a new orchard sprayer, you’ll want to think about it a bit. A sprayer is a major investment, about $50,000, not something to be taken lightly. And what you buy is likely to be with you for many years.
Dr. Andrew Landers, an agricultural engineer at New York State’s Cornell University, is one of the nation’s few researchers—the only one at a land-grant university—who keeps track of new orchard spray technology, researches better techniques, evaluates new machines and sprayer concepts, and teaches growers and students ways to provide more effective and safer spraying.
In an interview with Good Fruit Grower, he offered a checklist of things to consider when purchasing a new sprayer.
1. What’s your plan?
The first thing to consider is your farm’s existing situation and plans for the future, he said. You may be buying more land and expanding your orchards, maybe bringing in the next generation, in which case you’ll need new, remodeled, or additional sprayers.
You’re probably changing the design of your orchard, moving from bigger trees to smaller ones that are shorter and narrower in the row. Alleys are probably narrower, too. The old airblast sprayer technology you’ve been using since the 1960s may no longer be required.
“Many growers are caught between a rock and hard place,” Landers said. “They’ve already expanded their acreage and have pushed their sprayers to the limit. There’s only so much time available to spray, and growers who have extended their spray interval or reduced spray volumes may not be getting adequate coverage. This can result in reduced fruit quality or resistance of pests to pesticides.”
2. What’s your time situation?
Timeliness is important. You have to consider the area you need to spray, the frequency with which you need to do it, and the characteristics of your land, your weather, and the workload of the farm, he said.
Most modern pesticides have short residual lives, need to be precisely targeted to the life cycle of the disease or insect, or need to be applied in a narrow window for proper thinning or prevention of diseases like apple scab and fireblight.
3. Look at alternative spraying techniques.
“There are alternatives to airblast sprayers,” Landers said. The concept of bombing an orchard with a blast of spray-laden air is an old one that has been refined in recent years.
Modern systems include directed deposition sprayers, tower sprayers that use multiple small fans rather than a single large one, tree sensing systems that turn the sprayer off when there’s no target to spray, and sprayers that automatically adjust airflow and reduce fan speed for smaller trees or smaller canopies.
Some modern orchards may need no supplemental airflow at all. If a tree wall becomes thin enough, coverage may be adequate from nozzles spraying directly without the benefit of a blast of air. “Do you need air assistance?” he asks.
4. Can you build or modify a sprayer?
There are ways to bring new life to existing sprayers, Landers said. There are catalogs filled with sprayer parts a do-it-yourselfer can buy and install. Kits can transform airblast sprayers into tower sprayers. You can add on a rate controller that will allow you to dial in application volume and automatically adjust flow rates to compensate for hills and valleys in the orchard.
You can add on a fill system that will make pesticide handling safer and easier. You can add a tank washing system—a secondary water tank and a rotating ball nozzle—that will make tank rinsing a much less arduous procedure.
Modern nozzles are all color coded and plastic, easy to replace, and with antidrip features.
Old-style sprayers were often controlled with boat-style cables. “Electric is the way to go,” Landers said. “They are better for the operator, and safer.”
Some new companies offer new services in custom building or modifying sprayers.
One way to speed up spraying is to build or buy an over-the-row, multiple-row sprayer in which nozzles are suspended on a vertical boom from an overhead gantry. A few growers are using them.
Landers said American growers should look to Europe, where some of these ideas have been developed and implementation is more advanced.
5. Custom spraying?
In field crops, Landers said, it is quite common for growers to hire custom applicators to spray their crops. This allows use of larger sprayers on specialized vehicles that move fast and get the job done in a timely manner.
Orchardists, who tend to make more applications of more materials each season than do, for example, corn or soybean growers, have tended to own their own equipment and do their own work or hire workers to do it.
It’s hard to imagine an orchardist who didn’t own a sprayer at all, but it’s not hard to imagine that an orchardist could hire people to help out on some acreage, or put someone on the farm to work as a custom applicator for neighbors. That would allow investment in the most modern and efficient sprayer technology.
Tips when choosing
Landers also offers a laundry list of specific considerations growers should look for in sprayers. Here are some:
- Durability is important. How well made is the sprayer? Generally, U.S.-sprayers tend to be overbuilt compared to European technology, which can seem frail by comparison.
- Buy good tanks. They should be stainless steel or modern plastic.
- Shelter your sprayer. If you’ve spent $45,000 for a sprayer, it should be worthy of being protected from the elements.
- Centrifugal pumps are cheaper, but diaphragm pumps are better.
- Filtration is next to godliness. Filter the spray water to keep nozzles from clogging, and make sure filters are accessible for cleaning.
- Pipes and hoses should be large bore for good flow and low foaming, and long enough so they won’t kink.
- The chassis should be light but strong. Sprayer weight is an issue to prevent soil compaction. Tandem axles with two tires on each side are a good choice.
- Hitching is something to consider. How easy is it to hook up the sprayer, and how well will the sprayer follow the tractor?
- Dealer service is important. The dealer need not be nearby physically, but must be able to respond with parts and service.
- Ease of maintenance. Is it easy to drain and rinse the tank? Are filters self-flushing?
- How much power will the sprayer require? With narrower alleys, you may be able to use smaller sprayers and smaller tractors, but horsepower needs to be adequate.
- How sophisticated is your sprayer operator? Operator comfort and safety are very important. “Why not ask him what he thinks are important features?” Landers said. “He may be capable of effectively using GPS and auto steering.”
Landers is the author of a new book, Effective Vineyard Spraying, that can be ordered online at www.effective spraying.com. He is currently working on an orchard version.